The Orthogonal Frequency Division Multiplexing (OFDM) technology requires a characteristic of mutual orthogonality between subcarriers, and is very sensitive to a frequency offset. Under the condition that a frequency offset exists, orthogonality between OFDM subcarriers may be damaged, and ICI may be generated. Particularly under the condition of a large frequency offset, since energy of an adjacent carrier leaks relatively large, system performance may be sharply deteriorated if ICI is not eliminated.
Therefore, solving the problem of ICI becomes one of core problems of the OFDM technology. Various methods for solving the frequency offset problem are proposed at present, which are mainly divided into time-domain methods and frequency-domain methods. However, these methods may not well solve the problem of ICI caused by a large frequency offset. Or, a part of a frequency offset value may be eliminated in a time domain by virtue of a concept of interpolation, but such a method may still not solve the problem of poor performance under the condition of high order modulation or large frequency offset. Or, a part of the frequency offset value may be eliminated in a frequency-domain convolution manner, but such a method costs too much in implementation, and has poorer practicability. Or, a part of the frequency offset value may be eliminated by a method like frequency-domain filtering, but since the filter coefficients are symmetric, adopting the symmetric filter coefficients under the condition of a large frequency offset may cause certain performance loss, and the loss is more obvious particularly under the condition of high code rate.